DataSet.CreateDataReader Method (DataTable[])

Returns a DataTableReader with one result set per DataTable.

Namespace:  System.Data
Assembly:  System.Data (in System.Data.dll)

public DataTableReader CreateDataReader(
	params DataTable[] dataTables
)

Parameters

dataTables
Type: System.Data.DataTable[]
An array of DataTables providing the order of the result sets to be returned in the DataTableReader.

Return Value

Type: System.Data.DataTableReader
A DataTableReader containing one or more result sets, corresponding to the DataTable instances contained within the source DataSet. The returned result sets are in the order specified by the dataTables parameter.

In order to ensure that the order of the result sets within the returned DataTableReader, if a DataTable within the DataSet is empty, it is represented by an empty result set within the returned DataTableReader. Because this overloaded version allows you to supply a list of DataTable instances as parameters, you can specify the order in which the result sets appear within the returned DataTableReader.

This example, a Console application, creates three DataTable instances and adds each to a DataSet. The example calls the CreateDataReader method and displays the contents of the returned DataTableReader. Note that the order of the result sets in the DataTableReader is controlled by the order of the DataTable instances passed as parameters. The example displays the results in the Console window.


static DataTable customerTable;
static DataTable productTable;
static DataTable emptyTable;

static void Main()
{
    DataSet dataSet = new DataSet();

    // Add some DataTables to the DataSet, including
    // an empty DataTable:
    emptyTable = new DataTable();
    productTable = GetProducts();
    customerTable = GetCustomers();

    dataSet.Tables.Add(customerTable);
    dataSet.Tables.Add(emptyTable);
    dataSet.Tables.Add(productTable);
    TestCreateDataReader(dataSet);

    Console.WriteLine("Press any key to continue.");
    Console.ReadKey();
}

private static void TestCreateDataReader(DataSet dataSet)
{
    // Given a DataSet, retrieve a DataTableReader
    // allowing access to all the DataSet's data.
    // Even though the dataset contains three DataTables,
    // this code will only display the contents of two of them,
    // because the code has limited the results to the 
    // DataTables stored in the tables array. Because this
    // parameter is declared using the ParamArray keyword, 
    // you could also include a list of DataTable instances 
    // individually, as opposed to supplying an array of 
    // DataTables, as in this example:
    using (DataTableReader reader = 
       dataSet.CreateDataReader(productTable, emptyTable))
    {
        do
        {
            if (!reader.HasRows)
            {
                Console.WriteLine("Empty DataTableReader");
            }
            else
            {
                PrintColumns(reader);
            }
            Console.WriteLine("========================");
        } while (reader.NextResult());
    }
}

private static DataTable GetCustomers()
{
    // Create sample Customers table, in order
    // to demonstrate the behavior of the DataTableReader.
    DataTable table = new DataTable();

    // Create two columns, ID and Name.
    DataColumn idColumn = table.Columns.Add("ID", typeof(int));
    table.Columns.Add("Name", typeof(string));

    // Set the ID column as the primary key column.
    table.PrimaryKey = new DataColumn[] { idColumn };

    table.Rows.Add(new object[] { 1, "Mary" });
    table.Rows.Add(new object[] { 2, "Andy" });
    table.Rows.Add(new object[] { 3, "Peter" });
    table.Rows.Add(new object[] { 4, "Russ" });
    return table;
}

private static DataTable GetProducts()
{
    // Create sample Products table, in order
    // to demonstrate the behavior of the DataTableReader.
    DataTable table = new DataTable();

    // Create two columns, ID and Name.
    DataColumn idColumn = table.Columns.Add("ID", typeof(int));
    table.Columns.Add("Name", typeof(string));

    // Set the ID column as the primary key column.
    table.PrimaryKey = new DataColumn[] { idColumn };

    table.Rows.Add(new object[] { 1, "Wireless Network Card" });
    table.Rows.Add(new object[] { 2, "Hard Drive" });
    table.Rows.Add(new object[] { 3, "Monitor" });
    table.Rows.Add(new object[] { 4, "CPU" });
    return table;
}

private static void PrintColumns(DataTableReader reader)
{
    // Loop through all the rows in the DataTableReader
    while (reader.Read())
    {
        for (int i = 0; i < reader.FieldCount; i++)
        {
            Console.Write(reader[i] + " ");
        }
        Console.WriteLine();
    }
}


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
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